The present invention relates to an underwater camera for deep sea use, comprising a pressure-tight and substantially cylindrical housing enclosing a camera, the wall of said housing having, in the region of the camera objective, a thickened portion in which is disposed a window opposite the objective.
In U.S. Pat. No. 3,261,274 an underwater camera is disclosed which operates in conjunction with a grab which is suspended from a cable and is lowered onto the sea bed. The camera comprises a pressure-tight, cylindrical housing, which is arranged with the axis of the cylinder substantially vertical. The housing is made pressure-tight and encloses a camera which looks downward through a window arranged on the bottom end wall. The arrangement of the window in the end wall necessitates a housing of considerable dimensions. If this housing is to withstand high sea pressures, it must have extraordinarily thick walls, which results in the weight being high. A high weight is of no great significance with that camera, because it is used in conjunction with a grab hanging on a cable.
In German Auslegeschrift No. 1,911,782 a free-fall grab is disclosed which comprises buoyancy members consisting of glass spheres, which are arranged one above the other. The uppermost glass sphere is separable and contains a camera which looks outwardly and obliquely through the glass sphere onto the sea bed. Therefore, the glass sphere not only serves as a buoyancy member for the free-fall grab, but also as a pressure-tight housing for the camera. An important disadvantage of this arrangement consists in that special measures are necessary for avoiding distortion of the picture because of the spherical wall of the glass sphere. Moreover, an initial condition for the arrangement is the use of glass for the pressure-tight housing of the camera. Considerable disadvantages arise as a consequence, more especially when it is intended that the camera with the housing should be made particularly small, so that they can be accommodated together with the pressure-tight housing by the free-fall grab.
The present invention has for its object an underwater camera for deep sea use, where the pressure-tight housing can be made particularly small and which can be constructed of a non-transparent material, such as aluminum. In addition, the underwater camera of the present invention can be particularly light in weight and suitable for being fitted on free-fall grabs.
These objects of the present invention are achieved by a thickening of the housing comprising a cylindrical bead which is arranged eccentrically of the cylindrical housing and which projects over the window of the camera.
In a preferred embodiment of camera incorporating the principles of the present invention, a cylindrical pressure-tight housing as previously known is provided which, however, has a window arranged in the cylindrical wall. This positioning of the window requires a considerable wall thickness for transmitting the pressure of the window to the surrounding marginal portions of the opening for the window in the housing. However, a large wall thickness would result in considerable weight. The present invention avoids this disadvantages of excessive weight by the cylinder wall only being thicker in the region in which the window is situated, which thickness may be produced by simple machining, e.g. turning operation, the latter of which is also suitable for producing the remainder of the high pressure-tight housing itself.
A further feature of the invention consists in that the bead is flush with the cylindrical external surface of the housing on the side of the housing furthest from the window. The result of this construction is that the cylinder wall has its maximum thickness, such as is necessary for accommodating the window, only in the region of the latter, while in the region furthest from the window, it only has the thickness which is provided for the housing wall generally.
It is desirable for the side walls of the increased thickness bead to be bevelled. The intended purpose of such bevel is that a constant transition between the different wall thickness will result such that stress peaks in the material are avoided.
Due to the above features of the present invention, the housing of the underwater camera of the present invention can be made extremely small and light in weight. When being used in conjunction with free-fall grabs, the useful load of the latter can therefore be increased by an amount corresponding to the reduction in weight of the camera.
These and other objects, features and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.